Gate coupled voltage support for an output driver circuit

ABSTRACT

A method and apparatus for supporting a voltage in an output driver circuit and smoothing the response of the voltage to switching operations in the output driver circuit. A capacitive element, such as a capacitor or transistor, is coupled to the gate of a drive transistor in an output driver leg circuit of an output driver and to a switched signal voltage. By coupling the capacitive element to a signal voltage other than ground, a smaller capacitive element is required than that required for coupling the capacitive element to ground. An embodiment of the invention further includes a plurality of capacitive elements configured such that the voltage support is applied to the gate of the drive transistor in phases rather than all at once to smooth voltage response to drive transistor switching. Transistors having relatively longer effective channel lengths may be used as the capacitive elements to allow for additional phasing-in of the voltage support due to signal delay through the longer channels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/977,661,filed Oct. 15, 2001, now U.S. Pat. No. 6,433,593, issued Aug. 13, 2002,which is a continuation of application Ser. No. 09/633,925, filed Aug.8, 2000, now U.S. Pat. No. 6,351,159 B1, issued Feb. 26, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to voltage compensationtechniques in an output driver for an integrated circuit. Moreparticularly, the present invention relates to coupling a capacitiveelement between a drive transistor's gate and a power supply andphasing-in portions of a voltage-supporting capacitance at slightlydifferent times to smooth the compensating corrections.

2. State of the Art

As the sizes of semiconductor devices have reduced, so have the powersupply voltages driving the devices. With smaller power supply voltages,respective signals within the semiconductor devices have also becomesmaller and more susceptible to variance caused by the influence ofresistance, inductance, capacitance and switching within thesemiconductor device. Unintended variances on a signal line can lead toan inability to correctly detect a signal and to detecting a signal whenone was not intended. In either case, malfunctions and other signalerrors may occur as a result of the variances.

As shown in FIG. 1, an output 2 of a semiconductor device conventionallyincludes an output driver 4 between the primary semiconductor circuitry6 and the outputs 2. One purpose of the output driver 4 is to providesufficient power compensation for the output signal to ensure the signalis output with an appropriate signal strength.

FIG. 2 shows a conventional output driver circuit 8. For a conventionalsemiconductor die, each output of the die is coupled to each of constantvoltage signal lines envg<0> through envg<6> 10, 12, 14, 16, 18, 20 and22. Each of the constant voltage signal lines envg<0> through envg<6>10, 12, 14, 16, 18, 20 and 22 is further coupled to at least one outputdriver leg circuit 24, 26, 28, 30, 32, 34, 36, 38, 40, 42 and 44. Usingone of the output driver leg circuits 44 coupled to envg<6> 22 as anexample, each output driver leg circuit conventionally includes a drivetransistor 46 and a switching transistor 48.

The output driver circuit 8 shown in FIG. 2 is configured as anopen-drain output driver. An open-drain configured output driver is onein which the drain of the drive transistor for each output driver legcircuit 24, 26, 28, 30, 32, 34, 36, 40, 42 and 44 is not coupled tocircuitry within the semiconductor, but is directly coupled to anexternally accessible contact, such as a bond pad. In a conventionalopen-drain configured output driver circuit 8 that has its outputimpedance controlled, such as that shown in FIG. 2, the drive transistor46 will have its gate 50 set to a controlled voltage (typically 1.3 V to1.4 V) such that the drive transistor 46 will be in saturation as muchas possible while still achieving the required output drive. Theswitching transistor 48 is placed between the drive transistor 46 and areference potential 53 such as a ground, to allow for switching thedrive transistor 46 between off and on states.

The array of output driver leg circuits 24, 26, 28, 30, 32, 34, 36, 38,40, 42 and 44 are conventionally configured such that the transistorsused for the output driver leg circuits 32 and 40 coupled to constantvoltage signal line envg<5> 20 are approximately half the physical sizeof the transistors used for the output driver leg circuits 34 and 44coupled to constant voltage signal line envg<6> 22. Likewise, thetransistors used for the output driver leg circuits 30 and 38 coupled toenvg<4> 18 are approximately half the physical size of the transistorsused for the output driver leg circuits 32 and 40 coupled to constantvoltage signal line envg<5> 20. This pattern of using transistorsapproximately half the physical size of the transistors coupled to thenext sequential envg< > signal line continues down to the transistorscoupled to envg<0> 10. The physical size of the output driver legcircuit 42 is half the sum of the physical sizes of both output driverleg circuits 28 and 36. The output drive supplied by an output driverleg circuit is proportional to the physical size of the transistors usedfor that output driver leg circuit. By including output driver legcircuits, each providing a different output drive amount, a combinationof different output driver leg circuits can provide a wide range ofavailable output drive. Additional circuitry well-known to those ofordinary skill in the art determines how much output drive is needed fora particular output signal and controls which output driver leg circuitsare switched “ON” and “OFF” to provide an appropriate level of outputdrive.

Though there are many advantages to selectively switching the variousoutput driver leg circuits 24, 26, 28, 30, 32, 34, 36, 38, 40, 42 and 44“ON” and “OFF,” the “ON” and “OFF” action causes undesirable shifts inthe drive transistor's gate 50 voltage due to potential changes thatcouple back through the drive transistor's gate 50. Namely, the drivetransistor's gate voltage may drop 100 mV from its desired level, forexample, when the drive transistor 46 is switched to an “ON” state whichwill reduce the output drive from its intended target. One method ofcompensating for this drop in voltage, as shown in FIG. 3, is to couplea capacitor 54 between the drive transistor's gate 58 and a groundpotential. With the capacitor in place, when the drive transistor 56 isturned “ON” indirectly by the switching transistor 62, the voltage onthe drive transistor's gate 58 begins to drop toward a ground potential,but the capacitor 54, also referenced to the ground potential, reducesthe voltage drop experienced. The larger the capacitor 54 used, thesmaller the voltage dip caused when the drive transistor 56 is turnedon. One example of a support circuit having capacitive support of thiskind used in an output driver circuit may be found in Rambus DynamicRandom Access Memory (RDRAM) part 288MD-400-800, designed by Rambus,Inc. of Mountain View, Calif.

The repeated “ON”—“OFF” action, with the voltage on the drivetransistor's gate 58 working to remain constant over a period of time,results in a square wave signal at the drive transistor's gate 58. Theoutput driver leg circuits' control circuit then tries to set the DCaverage of the drive transistor's gate 58 voltage equal to the desiredvoltage. As an example, using the output driver leg circuit of FIG. 3,if constant voltage signal lines envg<6> 60 were set at an operatingvoltage of 1.4 V and the switching transistor 62 were turned on, thevoltage on the drive transistor's gate 58 would initially tend to bepulled down by the voltage on the drain of the switching transistor 62,perhaps to 1.3 V. The capacitor 54 on the drive transistor's gate 58 ofthe drive transistor 56 would then tend to reduce the voltage dropexperienced. If the switching transistor 62 were turned “ON” and neverturned “OFF,” the voltage on the gate 58 of the drive transistor 56would eventually reattain 1.4 V due to the controlling circuit's effect.For a typical output driver compensation circuit, however, the switchingtransistor 62 is not left “ON,” but is repeatedly switched “ON” and“OFF.” This toggling “ON” and “OFF” results in a square wave signal onconstant voltage signal lines envg<6> 60 which eventually reaches a DCaverage of 1.4 V, toggling, for example, between 1.35 V and 1.45 V.

These variances in the voltage level of constant voltage signal linesenvg<6> 60 result in variances in the output signal power which canresult in signal transmission errors. As a result, part specificationsare used to identify the maximum allowable variance for reliableoperation. For example, the specifications for the RDRAM 288MD-40-800,referenced previously, require that the voltage level on the drivetransistor's gate 58 have less than a 50 mV variance. To reduce thevariance of the drive transistor's gate 58 voltage to less than 50 mVrequires a substantial capacitor 54 (approximately 15 times the physicalsize of the associated drive transistor 56) coupled to each envg< >signal line. Where semiconductor space or “real estate” is precious,such a large capacitor for each output consumes a significant portion ofthe space available. It is therefore desirable to have an output drivecircuit with minimal voltage variance without using such a largecapacitor.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an output driver circuit for asemiconductor device, the output driver circuit including a plurality ofcompensating circuits which are capable of maintaining minimal variancein the drive transistor gate voltages without the use of excessivelylarge capacitors. According to a first aspect of the present invention,a capacitor is coupled to the gate of a drive transistor and to a signalvoltage. This signal voltage is established such that it opposes thevoltage shift caused by switching the switching transistor “ON.” Byreferencing the compensating capacitor to such a signal voltage, smallercapacitor sizes are needed to obtain the results offered by largecapacitors referenced to ground. An additional capacitor may also bereferenced to ground to provide additional compensation during thetransitions of the switching transistor and the signal voltage.

According to a second aspect of the present invention, the voltagecompensation provided to the gate of the drive transistor is added inphases, one portion at a time, to smooth out the response to thecompensation correction. In one embodiment, rather than applying thecompensation all at once, the compensation is added in two portions orphases. In another embodiment, the compensation is added in threephases. In yet another embodiment, the compensation is furthersupplemented with an additional capacitor referenced to a groundpotential. In yet another embodiment, transistors having relatively longeffective channel lengths are used to cause a delayed compensation toprovide a fourth phase of compensation.

According to a third aspect of the present invention, existing outputdrivers are reworked to meet application specifications by reconnectingexisting transistors within the semiconductor die to enable narrowerspecification parameters without large capacitors.

An electronic system is disclosed comprising a processor, a memorydevice, an input, an output and a storage device, at least one of whichincludes an output driver circuit with a compensating circuit having atleast one capacitor coupled between the gate of a drive transistor and asignal voltage. A semiconductor wafer is also disclosed including anoutput driver circuit according to one or more embodiments of thepresent invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The nature of the present invention as well as other embodiments of thepresent invention may be more clearly understood by reference to thefollowing detailed description of the invention, to the appended claims,and to several drawings herein, wherein:

FIG. 1 is a simplified block diagram of a prior art semiconductor deviceoutput;

FIG. 2 is a circuit diagram of a prior art output driver circuit array;

FIG. 3 is a circuit diagram of a prior art compensating circuit of anoutput driver circuit;

FIG. 4 is a circuit diagram illustrating a compensating circuit of afirst embodiment of the present invention;

FIG. 5 is a circuit diagram illustrating a compensating circuit of asecond embodiment of the present invention;

FIG. 6 is a circuit diagram illustrating a compensating circuit of athird embodiment of the present invention;

FIG. 7 is a circuit diagram illustrating a compensating circuit of afourth embodiment of the present invention;

FIG. 8 is a circuit diagram illustrating an output driver circuit whichhas been reworked to include an embodiment of the present invention;

FIG. 9 is a block diagram of an electronic system including an outputdriver circuit according to an embodiment of the present invention; and

FIG. 10 is a diagram of a semiconductor wafer having at least one outputdriver circuit configured according to an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 4 is a circuit diagram of an output driver leg circuit 64 of anoutput driver circuit according to a first embodiment of the invention.According to an embodiment of the present invention, rather thancoupling a compensating capacitor between the signal line envg<6> 68 anda ground reference voltage, as is conventionally done in the art, asupport circuit 65 is coupled between the signal line envg<6> 68 and thesignal voltage (q) line 70 for switching the switching transistor 72“ON” which turns the drive transistor 74 “ON.” For this first embodimentshown in FIG. 4, the support circuit 65 includes a capacitor 66. It willbe understood by one of ordinary skill in the art that the capacitor 66shown in FIG. 4, and in other figures herein, is a transistor with itsdrain and source terminals coupled together in such a way that itresponds as a capacitor. As used herein, “capacitor” is intended to meanany capacitive element, including, without limitation, transistorsconfigured as capacitors, dedicated capacitors, and other devices of acapacitive nature. By coupling a capacitor 66 between the signal voltage(q) line 70 and the signal line envg<6> 68, a significantly smallercapacitance is required to support the signal line envg<6> 68 voltageagainst being pulled down by the switching transistor 72 being turned“ON.” In operation, as the signal voltage q is provided on signalvoltage (q) line 70 to switch “ON” the switching transistor 72 and,thus, activate the drive transistor 74, the charge stored on thecapacitor 66 pushes up against the voltage on signal line envg<6> 68 asthe connection to ground through the switching transistor 72 pulls downon the voltage on signal line envg<6> 68 through the gate of drivetransistor 74.

FIG. 5 is a circuit diagram of a compensating circuit 76 of an outputdriver circuit according to a second embodiment of the invention. In theembodiment shown in FIG. 5, a support circuit 78 is placed between thesignal line envg<6> 80 and the signal voltage (q) line 82 used to turn“ON” the switching transistor 84 to initiate the drive transistor 86. Inthis embodiment, however, the support circuit 78 comprises twotransistors 88 and 90 to apply the voltage support in two separatephases rather than all at once. In operation, when the signal voltage qis provided on the signal voltage (q) line 82 to switch on the switchingtransistor 84 and, thus, activate the drive transistor 86, the initialphase of the support is provided to the signal line envg<6> 80 throughthe transistor 88 directly coupled between the signal line envg<6> 80and the signal voltage (q) line 82. The second phase of the support isprovided to the signal line envg<6> 80 through the p-channel transistor90 coupled between the signal voltage (q) line 82 and the transistor 88coupled directly to the signal line envg<6> 80. Because of the phasingdelays in compensation caused by placing a p-channel transistor 90between the transistor 88 and the signal voltage (q) line 82, thecompensation through that leg of the support circuit 78 is slower thanwith the first phase.

One factor affecting the response of the voltage level on the signalline envg<6> 80 to the added support, and to the signal line envg<6> 80being pulled toward ground by the switching transistor 84 turning “ON,”is that there is a delay in the voltage on the signal line envg<6> 80being pulled down from the time the signal voltage q is applied to thesignal voltage (q) line 82. If too much support is applied to the signalvoltage (q) line 82 before the voltage has been fully affected by theswitching of the switching transistor 84, the signal line envg<6> 80 maybe over-supported, causing more variance in the signal line envg<6> 80voltage. Applying support to the signal line envg<6> 80 in phases ratherthan all at once allows for a smoother response to the added supportand, thus, a more steady voltage level on the signal line envg<6> 80.

FIG. 6 is a circuit diagram of a compensating circuit 92 of an outputdriver circuit according to a third embodiment of the invention. In theembodiment shown in FIG. 6, a support circuit 94 is placed between thesignal line envg<6> 96, a first signal voltage (q) line 98 used to turnon the switching transistor 100 to initiate the drive transistor 102 anda second signal voltage (qL) line 110. In this embodiment, however, thesupport circuit 94 comprises three transistors 112, 114 and 115 to applythe support in three separate phases rather than all at once. For thisembodiment, a signal voltage q is applied to the first signal voltage(q) line 98 and a signal voltage qL is applied to the second signalvoltage (qL) line 110. The first phase of support is provided throughthe transistor 112 coupled directly to both the signal line envg<6> 96and the first signal voltage (q) line 98. The second phase of support isprovided through the transistor 114 coupled directly to both the signalline envg<6> 96 and the second signal voltage (qL) line 110. The thirdphase of support is provided through the p-channel transistor 115 andthe transistor 112 coupled between the signal line envg<6> 96 and thefirst signal voltage (q) line 98. Additionally, as shown with respect toa fourth embodiment in FIG. 7, a capacitive element in the form of atransistor 117 may also be added between the signal line envg<6> 116 anda ground reference to provide support for the voltage on that signalline to further enhance the support provided.

As will be clear to one of ordinary skill in the art from theembodiments shown thus far, any number of support phases may be used tosupport the voltage on a signal line in different phasing steps ratherthan all at once. By supporting the voltage on the envg< > signal linein phasing steps, the response of the voltage level to switching on theswitching transistor is smoother and less likely to spike or dip.Furthermore, by placing at least a portion of the supporting elementsbetween the signal line and a reference voltage, smaller capacitancesare required than when coupling the supporting elements to ground.

Another aspect of the invention, which provides another phasingdimension to the phases previously described herein, is selection of theeffective channel length of the capacitors or transistors used tosupport the envg< > signal lines. The effective channel length of thecapacitors and transistors used to support the envg< > signal linesimpacts the smoothness of the compensating corrections. For example, theshorter the effective channel length of a transistor or capacitor, thefaster compensation at one end of the channel affects the voltage at theother end of the channel. Conversely, the longer the effective channellength of the transistor or capacitor, the slower compensation at oneend of the channel affects the voltage at the other end. By determining,through simulation and/or experiment, the capacitive support and timingrequired to best and most smoothly support the voltage on the signallines envg< >, an appropriate effective channel length may be determinedby one of ordinary skill in the art. The surrounding circuitry andparticular semiconductor material used will affect the timing andsupport needed for a given application. One of ordinary skill in the artwill be able to make the needed calculations for a particularapplication.

As will also be clear to one of ordinary skill in the art, one or moreembodiments of supporting circuitry may be included on each outputdriver leg circuit of an output driver circuit, or it may be preferablein some applications to include no forms of supporting circuitry on aparticular output driver leg circuit. For example, because the outputdriver leg circuit transistors become respectively smaller in physicalsize, by half, than the preceding transistor in a series of outputdriver leg circuits, the voltage support added by each of these circuittransistors similarly becomes respectively smaller. Because thephysically smaller transistors have, respectively, a smaller effect onthe overall voltage when they are switched in as support, phasecompensation of smaller transistor support may not be necessary ordesired in a particular application. As with determining the timingrequired for adequate support of the voltage on the voltage (q) signallines, which support circuits need phased support configurations mayreadily be determined by one of ordinary skill in the art. If multiplephases of compensation are not needed, one or more capacitive elementscoupled between the signal line envg< > and a grounded reference issufficient.

The present invention may also be incorporated into existing outputdriver circuits. FIG. 8 shows an embodiment of the present inventionwherein existing circuitry on a semiconductor die was modified to meet ahigher standard of voltage maintenance on the signal lines envg< >. Asshown in FIG. 8, an output driver circuit compensating array 118 isprovided having a plurality of signal lines envg<0> through envg<6> 120,122, 124, 126, 128, 130 and 132. Before modification, the compensatingarray 118 included only a plurality of capacitive elements 134, 136,138, 140, 142, 144 and 146 coupled between the signal lines envg<0>through envg<6> 120, 122, 124, 126, 128, 130 and 132 and ground. Toimprove the ability of the compensating array 118 to control and smooththe voltage response on each envg< > signal line to switching “ON”driving transistors, support circuitry 148 and 150 was added. The firstsupport circuitry 148 is coupled primarily to signal line envg<6> 132and includes a modified array of transistors 152, 154, 156, 158 and 160and one p-channel transistor. Modifying the existing array oftransistors 152, 154, 156, 158 and 160 to provide support to the voltageon signal line envg<6> 132 in phases permits voltage variance parametersnarrower than previously accomplished using the same existing circuitry.

The existing array of transistors 152, 154, 156, 158 and 160 has beenmodified, in this example, to provide two primary phases of support inaddition to the support provided by the capacitive element 146 coupledbetween signal line envg<6> 132 and ground. For the first transistorarray: a first transistor 152 is modified to be entirely coupled betweensignal line envg<6> 132 and ground; a second transistor 154 has its gategrounded so as to be ineffective; a third transistor 156 is coupledbetween the signal line envg<6> 132, a first signal voltage (q) signalline 164 and the drain of the p-channel transistor 162 which is alsocoupled to the first signal voltage (q) signal line 164; and a fourthtransistor 158 and a fifth transistor 160 are each coupled in parallelwith the third transistor 156. The second support circuitry 150 includesa second transistor array with a plurality of transistors 166, 168, 170,172 and 174 and is modified to provide phased support to the voltage ofsignal line envg<5> 130. In the second transistor array: a firsttransistor 166 is coupled between signal line envg<5> 130 and ground; asecond transistor 168 and a fourth transistor 172 have their gatesgrounded so as to be ineffective; a third transistor is coupled betweenthe signal line envg<5> 130, the drain of the p-channel 162, and thefirst signal voltage (q) signal line 164; and a fifth transistor 174 iscoupled between the signal line envg<5> 130 and voltage (qL) signal line176. As described in conjunction with previous embodiments, coupling thetransistors between a voltage line, such as first signal voltage (q)signal line 164 and voltage (qL) signal line 176, and a signal lineenvg< > reduces the physical size and capacity of the capacitor requiredto meet a particular set of specifications, and phasing the supportsmooths the response of the voltage transitions caused by switching inthe supporting circuitry.

FIG. 9 is a block diagram of an electronic system 200 which includescomponents having one or more output driver circuits 206 configuredaccording to one or more embodiments of the present invention. Theelectronic system 200 includes a processor 204 for performing variouscomputing functions, such as executing specific software to performspecific calculations or tasks. Additionally, the electronic system 200includes one or more input devices 208, such as a keyboard or a mouse,coupled to the processor 204 to allow an operator to interface with theelectronic system 200. The electronic system 200 also includes one ormore output devices 210 coupled to the processor 204, such outputdevices including such outputs as a printer, a video terminal or anetwork connection. One or more data storage devices 212 are alsoconventionally coupled to the processor 204 to store or retrieve datafrom external storage media (not shown). Examples of conventionalstorage devices 212 include hard and floppy disks, tape cassettes, andcompact disks. The processor 204 is also conventionally coupled to acache memory 214, which is usually static random access memory (“SRAM”),and to dynamic random access memory (DRAM) 202. It will be understood,however, that the one or more output driver circuits 206 configuredaccording to one or more of the embodiments of the present invention areincorporated into one or more of the cache memory, DRAM, input, output,data storage and processor devices 214, 202, 208, 210, 212, and 204.

As shown in FIG. 10, an output driver circuit 218 may be fabricated onthe surface of a semiconductor wafer 216 of silicon, gallium arsenide,or indium phosphide in accordance with one or more embodiments of thepresent invention. One of ordinary skill in the art will understand howto adapt such designs for a specific chip architecture or semiconductorfabrication process. Of course, it should be understood that the outputdriver circuit 218 may be fabricated on other semiconductor substratessuch as a Silicon-on-Insulator (SOI) substrate, a Silicon-on-Glass (SOG)substrate, a Silicon-on-Sapphire (SOS) substrate, or other semiconductormaterial layers on supporting substrates, and that the term “wafer” asemployed herein, is specifically intended to encompass such othersubstrates.

Although the present invention has been shown and described withreference to particular preferred embodiments, various additions,deletions and modifications that are obvious to a person skilled in theart to which the invention pertains, even if not shown or specificallydescribed herein, are deemed to lie within the scope of the invention asencompassed by the following claims.

What is claimed is:
 1. An output driver circuit having at least oneoutput driver leg circuit associated therewith, the at least one outputdriver leg circuit comprising: at least one drive transistor; at leastone switching transistor coupled to both the at least one drivetransistor and at least a first voltage signal line; and a supportcircuit coupled to a gate of the at least one drive transistor and tothe at least a first voltage signal line, the support circuit includingat least a first support element having an effective channel lengthbased, at least in part, on at least a first time when voltage supportis needed relative to a beginning of an activated cycle of the at leastone drive transistor.
 2. The output driver circuit of claim 1, whereinthe effective channel length of the at least a first support element islonger than an effective channel length of the at least one drivetransistor.
 3. The output driver circuit of claim 1, wherein the supportcircuit further comprises a switching element coupled to the gate of theat least one drive transistor and controlled during the activated cycleof the at least one drive transistor by at least one switching voltageother than ground.
 4. The output driver circuit of claim 3, wherein thesupport circuit further comprises a switching transistor coupled to theswitching element with the at least one switching voltage coupled to theswitching transistor.
 5. The output driver circuit of claim 4, whereinthe support circuit further comprises a second support element coupledto the at least a first support element and the at least one switchingvoltage, the second support element having an effective channel lengthbased, at least in part, on at least a second time when voltage supportis needed relative to the beginning of the activated cycle of the atleast one drive transistor.
 6. The output driver circuit of claim 5,wherein the support circuit further comprises a third support elementcoupled to the gate of the at least one drive transistor and to at leasta second switching voltage different from the at least one switchingvoltage, the third support element having an effective channel lengthbased, at least in part, on at least a third time when voltage supportis needed relative to the beginning of the activated cycle of the atleast one drive transistor.
 7. The output driver circuit of claim 1,wherein the support circuit further comprises at least another supportelement coupled to the gate of the at least one drive transistor and aground potential, the at least another support element having aneffective channel length based, at least in part, on at least anothertime when voltage support is needed relative to the beginning of theactivated cycle of the at least one drive transistor.
 8. A supportcircuit for smoothing a response of a voltage on a gate of a drivetransistor of an output driver circuit, comprising: a first supportelement for coupling to the gate of the drive transistor and to at leastone switching voltage, the first support element having an effectivechannel length based, at least in part, on at least a first time whenvoltage support is needed relative to a beginning of an activated cycleof the drive transistor; and a second support element coupled to thefirst support element and the at least one switching voltage, the secondsupport element having an effective channel length based, at least inpart, on at least a second time when voltage support is needed relativeto the beginning of the activated cycle of the drive transistor.
 9. Thesupport circuit of claim 8, further comprising a third support elementcoupled to the gate of the drive transistor and to at least a secondswitching voltage different from the at least one switching voltage, thethird support element having an effective channel length based, at leastin part, on at least the second time when voltage support is neededrelative to the beginning of the activated cycle of the drivetransistor.
 10. The support circuit of claim 9, further comprising atleast another support element coupled to the gate of the drivetransistor and a ground potential, the at least another support elementhaving an effective channel length based, at least in part, on at leastanother time when voltage support is needed relative to the beginning ofthe activated cycle of the drive transistor.
 11. An electronic systemcomprising: a processor; and at least one of an input device, an outputdevice, a memory device and a data storage device associated with theprocessor; wherein at least one component of the electronic systemcomprises an output driver circuit including a drive transistor having asupport circuit associated therewith, the support circuit including atleast one support element for coupling to a gate of the drive transistorand to at least one switching voltage, having an effective channellength based, at least in part, on at least a first time when voltagesupport is needed relative to a beginning of an activated cycle of thedrive transistor.
 12. The electronic system of claim 11, furthercomprising a second support element coupled to the at least one supportelement and the at least one switching voltage, the second supportelement having an effective channel length based, at least in part, onat least a second time when voltage support is needed relative to thebeginning of the activated cycle of the drive transistor.
 13. Theelectronic system of claim 12, wherein the support circuit furthercomprises at least another support element coupled to the gate of thedrive transistor and a ground potential, the at least another supportelement having an effective channel length based, at least in part, onat least another time when voltage support is needed relative to thebeginning of the activated cycle of the drive transistor.